Composite cellulosic products are often treated in order to impart desirable qualities such as insect resistance, durability and hardness. Such methods generally involve treating a composite product after it has been formed from component layers, or treating a surface layer prior to its lamination to core lamellae. Such core lamellae, if multilayered, are generally of layers which have been identically treated prior to their assembly into a composite product with the surface veneer.
A review entitled “Wood Composite Protection” [Gardner, Douglas J.; Tascioglu, Cihat; Walinder, Magnus E. P.; ACS Symposium Series (2003), 845 (Wood Deterioration and Preservation), 399-419] discloses the pre-assembly treatment of wood layers with a solution of CCA (page 404, second paragraph).
A Japanese Patent, JP 2001279917 to Hisao Iwamoto, discloses the treatment of a single veneer with an insecticide, followed by the attachment of the veneer to a surface veneer. The reference also discloses that a cosmetic coating can be applied to the surface veneer after assembly (paragraph 0013).
A German journal article entitled “Protective Treatment of Building Plywood” [Deppe, H. J.; Bundesanst. Mater., Berlin-Dahlem, Fed. Rep. Ger.; Holz als Roh-und Werkstoff (1986), 44(9), 333-40] discloses treatment of two layers—a surface layer and an underlayer (“core lamella”)—with a preservative by different processes prior to their assembly into a composite wood product. That the underlayer can be of multiple veneers (core lamellae) is also disclosed. A process which includes the treatment of the core lamella with and a simple immersion for the surface sheets is disclosed (see Conclusion). However, no applications involving the differential treatment of multiple wood layers such as veneers and laminates prior to assembly into a multilayer composite product are disclosed.
There exists a need for a process which can be used to prepare a wood product having an internal distribution of a process parameter such as, for example, a biocide, which can be precisely tailored such that the characteristics of the wood are appropriate for the wood's intended use. There is also a need for such a wood product.